I. Field of the Invention
The invention relates to a process for the preparation of certain cyano-substituted carboxylic acid esters by reacting an acid halide, an aldehyde and a water-soluble cyanide.
II. Description of the Prior Art
According to U.S. Pat. No. 3,835,176, addition of substituted cyclopropanecarbonyl halides and m-substituted benzaldehydes, if necessary dissolved in an aprotic solvent, to an aqueous solution of sodium cyanide or potassium cyanide and stirring of the mixture obtained until no more conversion takes place, affords the desired esters. The experiment described in Example 4 of the above U.S. patent was conducted in the absence of a solvent, with an unsaturated aqueous solution of sodium cyanide, with a 20% molar excess of the cyclopropanecarbonyl halide (calculated on aldehyde) and at a temperature of 0.degree. C.
Such a process has the disadvantages that the yield of the ester is relatively low and that keeping the temperature at 0.degree. C and using the said molar excess are expensive.
The process according to the present invention obviates these disadvantages and affords the desired esters by using specific solvents.